The subject invention relates to improved multilayered products and methods for manufacturing such products. More particularly, the subject invention relates to improved semiconductor products such as thin film read/write heads and methods for manufacturing such heads.
Underlayers play an important role in the formation of appropriate crystallographic textures of overlaid films in many applications. Typically, an underlayer is chosen such that the plane of atoms at the interface between layers provides an appropriate template to encourage growth of the overlaid film in a desired texture. Thus, the underlayer itself has to be grown in the correct texture and must have the correct lattice dimensions to promote this epitaxy.
Examples of a multilayer system contemplated here are the Cr/CoCrPt systems used in making thin film permanent magnets and Cr/Ta systems used for making electrical lead material. These permanent magnets and leads are important elements of thin film magnetic recording heads which are used in data storage devices like computer hard drives. A typical permanent magnet for such application may have a Cr underlayer having a thickness of about 20 angstroms to about 100 angstroms and a CoCrPt overlayer having a thickness of about 100 angstroms to about 1000 angstroms.
As requirements for greater storage density increase, there is a great need-to be able to make ultra sensitive heads which, while having enhanced properties, can be made reliably with reasonable manufacturing expense.
In accordance with the invention, there is provided a method for depositing multilayer films. The method includes the step of providing a substrate that defines a normal incident deposition angle that is perpendicular to the face of the substrate. A first film is deposited onto the substrate at a first deposition angle. A second film is deposited onto the substrate at a second deposition angle. In one embodiment of the invention, the first film may comprise Cr which is deposited at an angle greater than about 15xc2x0 from the normal incident deposition angle, preferably greater than about 20xc2x0 from the normal, and most preferably in the range of about 20-60xc2x0 from the normal. The second film may comprise CoCrPt or Ta which is deposited at a second deposition angle that deviates less from the normal than does the first deposition angle.
In accordance with another aspect of the invention, there is provided a method for depositing multilayer films, for example as part of a process for making a thin film magnetic recording head, comprising the steps of: providing a substrate which defines a normal angle of deposition incidence; depositing a layer of permanent magnet material at a first deposition angle relative to the normal angle; and depositing a layer of electrical lead material onto the substrate at a deposition angle relative to the normal angle that is greater than the first deposition angle.
In accordance with a further aspect of the invention, there is provided a method for depositing multilayer films onto a substrate to form improved permanent magnets used in making thin film magnetic recording heads. The method comprises the steps of providing a substrate which defines a normal angle of deposition incidence; depositing a first layer of material, such as Cr, onto the substrate at a first deposition angle relative to the normal angle, and depositing onto the substrate a second layer of material, such as CoCrPt, at a second deposition angle relative to the normal, the first deposition angle being greater than the second deposition angle.
The above and other aspects of the invention will be described in more detail below.